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Virtual 8086 Mode
In the 80386 microprocessor and later, virtual 8086 mode (also called virtual real mode, V86-mode, or VM86) allows the execution of real mode applications that are incapable of running directly in protected mode while the processor is running a protected mode operating system. It is a hardware virtualization technique that allowed multiple 8086 processors to be emulated by the 386 chip. It emerged from the painful experiences with the 80286 protected mode, which by itself was not suitable to run concurrent real-mode applications well. John Crawford developed the Virtual Mode bit at the register set, paving the way to this environment. VM86 mode uses a segmentation scheme identical to that of real mode (for compatibility reasons), which creates 20-bit linear addresses in the same manner as 20-bit physical addresses are created in real mode, but are subject to protected mode's memory paging mechanism. Overview The virtual 8086 mode is a mode for a protected-mode task. Conseq ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Intel 80386
The Intel 386, originally released as 80386 and later renamed i386, is a 32-bit microprocessor introduced in 1985. The first versions had 275,000 transistorsmit.edu—The Future of FPGAs (Cornell) October 11, 2012 and were the of many s and high-end s of the time. As the original implementation of the |
Multiuser DOS
Multiuser DOS is a real-time multi-user multi-tasking operating system for IBM PC-compatible microcomputers. An evolution of the older Concurrent CP/M-86, Concurrent DOS and Concurrent DOS 386 operating systems, it was originally developed by Digital Research and acquired and further developed by Novell in 1991. Its ancestry lies in the earlier Digital Research 8-bit operating systems CP/M and MP/M, and the 16-bit single-tasking CP/M-86 which evolved from CP/M. When Novell abandoned Multiuser DOS in 1992, the three master value-added resellers (VARs) DataPac Australasia, Concurrent Controls and Intelligent Micro Software were allowed to take over and continued independent development into Datapac Multiuser DOS and System Manager, CCI Multiuser DOS, and IMS Multiuser DOS and REAL/32. The FlexOS line, which evolved from Concurrent DOS 286 and Concurrent DOS 68K, was sold off to Integrated Systems, Inc. (ISI) in July 1994. Concurrent CP/M-86 The initial version of CP/M-8 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual DOS Machine
Virtual DOS machines (VDM) refer to a technology that allows running 16-bit/32-bit DOS and 16-bit Windows programs when there is already another operating system running and controlling the hardware. Overview Virtual DOS machines can operate either exclusively through typical software emulation methods (e.g. dynamic recompilation) or can rely on the virtual 8086 mode of the Intel 80386 processor, which allows real mode 8086 software to run in a controlled environment by catching all operations which involve accessing protected hardware and forwarding them to the normal operating system (as exceptions). The operating system can then perform an emulation and resume the execution of the DOS software. VDMs generally also implement support for running 16- and 32-bit protected mode software (DOS extenders), which has to conform to the DOS Protected Mode Interface (DPMI). When a DOS program running inside a VDM needs to access a peripheral, Windows will either allow this directly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Linux
Linux ( or ) is a family of open-source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991, by Linus Torvalds. Linux is typically packaged as a Linux distribution, which includes the kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name "GNU/Linux" to emphasize the importance of GNU software, causing some controversy. Popular Linux distributions include Debian, Fedora Linux, and Ubuntu, the latter of which itself consists of many different distributions and modifications, including Lubuntu and Xubuntu. Commercial distributions include Red Hat Enterprise Linux and SUSE Linux Enterprise. Desktop Linux distributions include a windowing system such as X11 or Wayland, and a desktop environment such as GNOME or KDE Plasma. Distributions inten ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Merge (software)
Merge is a software system which allows a user to run DOS/Windows 3.1 on SCO UNIX, in an 8086 virtual machine. History Merge was originally developed to run DOS under UNIX System V Release 2 on an AT&T 6300 Plus personal computer. Development of the virtual machine began in late 1984, and AT&T announced the availability of the machine on 9 October 1985, referring to the bundled Merge software as Simultask. (The PC 6300 Plus shipped with MS-DOS in 1985 though, because its Unix System V distribution was not ready until the end March 1986.) Merge was developed by engineers at Locus Computing Corporation, with collaboration from AT&T hardware and software engineers, particularly on aspects of the system that were specific to the 6300 Plus (in contrast to a standard IBM PC/AT). The AT&T 6300 Plus contained an Intel 80286 processor, which did not include the support for 8086 virtual machines (virtual 8086 mode) found in the 80386 and later processors in the x86 family. On the 802 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SCO UNIX
Xinuos OpenServer, previously SCO UNIX and SCO Open Desktop (SCO ODT), is a closed source computer operating system developed by Santa Cruz Operation (SCO), later acquired by SCO Group, and now owned by Xinuos. Early versions of OpenServer were based on UNIX System V, while the later OpenServer 10 is based on FreeBSD 10. History SCO UNIX/SCO Open Desktop SCO UNIX was the successor to the Santa Cruz Operation's variant of Microsoft Xenix, derived from UNIX System V Release 3.2 with an infusion of Xenix device drivers and utilities. SCO UNIX System V/386 Release 3.2.0 was released in 1989, as the commercial successor to SCO Xenix. The base operating system did not include TCP/IP networking or X Window System graphics; these were available as optional extra-cost add-on packages. Shortly after the release of this bare OS, SCO shipped an integrated product under the name of SCO Open Desktop, or ODT. 1994 saw the release of SCO MPX, an add-on SMP package. At the same time, AT&T com ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Virtual DOS Machine
Virtual DOS machines (VDM) refer to a technology that allows running 16-bit/32-bit DOS and 16-bit Windows programs when there is already another operating system running and controlling the hardware. Overview Virtual DOS machines can operate either exclusively through typical software emulation methods (e.g. dynamic recompilation) or can rely on the virtual 8086 mode of the Intel 80386 processor, which allows real mode 8086 software to run in a controlled environment by catching all operations which involve accessing protected hardware and forwarding them to the normal operating system (as exceptions). The operating system can then perform an emulation and resume the execution of the DOS software. VDMs generally also implement support for running 16- and 32-bit protected mode software (DOS extenders), which has to conform to the DOS Protected Mode Interface (DPMI). When a DOS program running inside a VDM needs to access a peripheral, Windows will either allow this directly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows ME
Windows Millennium Edition, or Windows Me (marketed with the pronunciation of the pronoun "me"), is an operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. It is the successor to Windows 98, and was released to manufacturing on June 19, 2000, and then to retail on September 14, 2000. It was Microsoft's main operating system for home users until the introduction of its successor Windows XP in October 2001. Windows Me was targeted specifically at home PC users, and included Internet Explorer 5.5 (later default was Internet Explorer 6), Windows Media Player 7 (later default was Windows Media Player 9 Series) and the new Windows Movie Maker software, which provided basic video editing and was designed to be easy to use for consumers. Microsoft also incorporated features first introduced in Windows 2000, which had been released as a business-oriented operating system seven months earlier, into the graphical user interface ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows 98 SE
Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS. Windows 98 is a web-integrated operating system that bears numerous similarities to its predecessor. Most of its improvements were cosmetic or designed to improve the user experience, but there were also a handful of features introduced to enhance system functionality and capabilities, including improved USB support and accessibility, as well as support for hardware advancements such as DVD players. Windows 98 was the first edition of Windows to adopt the Windows Driver Model, and introduced features that would become standard in future generations of Wind ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows 98
Windows 98 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of Microsoft Windows operating systems. The second operating system in the 9x line, it is the successor to Windows 95, and was released to manufacturing on May 15, 1998, and generally to retail on June 25, 1998. Like its predecessor, it is a hybrid 16-bit and 32-bit monolithic product with the boot stage based on MS-DOS. Windows 98 is a web-integrated operating system that bears numerous similarities to its predecessor. Most of its improvements were cosmetic or designed to improve the user experience, but there were also a handful of features introduced to enhance system functionality and capabilities, including improved USB support and accessibility, as well as support for hardware advancements such as DVD players. Windows 98 was the first edition of Windows to adopt the Windows Driver Model, and introduced features that would become standard in future generations of Win ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Windows 95
Windows 95 is a consumer-oriented operating system developed by Microsoft as part of its Windows 9x family of operating systems. The first operating system in the 9x family, it is the successor to Windows 3.1x, and was released to manufacturing on July 14, 1995, and generally to retail on August 24, 1995, almost three months after the release of Windows NT 3.51. Windows 95 merged Microsoft's formerly separate MS-DOS and Microsoft Windows products, and featured significant improvements over its predecessor, most notably in the graphical user interface (GUI) and in its simplified "plug-and-play" features. There were also major changes made to the core components of the operating system, such as moving from a mainly cooperatively multitasked 16-bit architecture to a 32-bit preemptive multitasking architecture, at least when running only 32-bit protected mode applications. Accompanied by an extensive marketing campaign, Windows 95 introduced numerous functions and features that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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